Limited slip differentials generally include a hydraulically actuated friction clutch pack that may be actuated to retard relative rotation of at least one of the side gears relative to the differential case. Limited slip differentials may include a non-rotating differential housing and a differential case rotatably supported within the differential housing. The differential case may be driven by an input shaft through a ring gear attached to a flange extending outwardly from the differential case. The differential case may house a pair of side gears, a pair of pinion gears, and a pinion shaft to allow speed differential between a pair of opposite output shafts. A friction clutch pack may be disposed between the side gear and the differential case. The friction clutch pack may comprise a plurality of friction discs that are alternately splined onto the side gear and the differential case.
A hydraulically actuated piston may be disposed within a piston chamber and may be configured to actuate (e.g., compress) the clutch pack and retard any speed differential between the side gear and the differential case. This may result in a retardation of any speed differential between the output shafts. A pump may be employed to provide pressurized hydraulic fluid to actuate the piston and engage the clutch pack. For example and without limitation, a gerotor pump may be provided with an inner gear attached to one of the side gears and an outer gear rotating with the differential case. Whenever the side gear is rotating, the pump may generate a pressurized flow of hydraulic fluid to the piston chamber. When the hydraulic pressure reaches a predetermined value, a portion of the fluid being pumped into the piston chamber is released and collected in a non-rotating plenum for recirculation through the piston chamber.
When the pump is positioned outside of the differential housing or the axle housing (i.e., an external hydraulic limited slip differential), some form of hydraulic bulkhead is generally required to provide a passageway for the hydraulic fluid to be supplied to the differential. The need for a hydraulic bulkhead may require that the axle housing have a particular configuration and/or certain features to enable this hydraulic fluid passageway. The axle housing may also generally be required to have a particular configuration and/or certain features to prevent rotation of the hydraulic bulkhead and/or its components.
If the axle housing needs to meet these multiple requirements, it may make the manufacturing of the axle housing more complex, complicated, and costly. For example, tight tolerances and/or various additional seals may be necessary in order to ensure that seals (e.g., o-rings) on the high pressure side of the hydraulic bulkhead are able to withstand the load from the plenum resisting rotation and prevent leakage. It may be desirable to reduce and/or minimize the manufacturing requirements for the axle housing that may still allow for the same level of functionality as existing axle housings utilized in hydraulic limited slip differentials.